1. Field of the Invention
This invention relates to a disc cartridge for housing a disc-shaped recording medium, such as an optical disc or a magneto-optical disc, loaded on a recording and/or reproducing apparatus.
2. Description of the Related Art
There has hitherto been used a disc cartridge housing an optical disc, a magneto-optical disc or a magnetic disc and which is loaded therewith on a recording and/or reproducing apparatus.
As this type of the disc cartridge, there is known such a device described in the U.S. Pat. No. 4,510,546.
With the disc cartridge described in these publications, a disc as a information recording medium is rotationally housed within a main cartridge body unit which is rectangular in shape. The main cartridge body unit has a recording and/or reproducing opening for allowing a portion of the housed disc to be exposed to outside across the inner and outer rims of the disc. This main cartridge body unit carries a shutter member, rectangular in cross-section, adapted to be moved along the front side of the main cartridge body unit for opening/closing the recording and/or reproducing opening. This shutter member is moved parallel to the one side at a center portion of the main cartridge body unit along the front surface of the main cartridge body unit to open/close the recording and/or reproducing opening, so that, at the corner portions of the rectangular main cartridge body unit, there are formed regions not covered by the shutter member and not faced by the magnetic disc. Thus, in these regions, there are provided cartridge supporting portions engaged or supported by the positioning pins provided on the recording and/or reproducing apparatus when the disc cartridge is loaded on the recording and/or reproducing apparatus.
As a disc cartridge housing a disc as an information recording medium, there is known such a one as described in the U.S. Pat. No. 4,614,990.
In the disc cartridge described in this Publication, a disc is rotatably housed in a rectangular main cartridge body unit. The main cartridge body unit is provided with a recording and/or reproducing opening for exposing part of the magnetic disc housed therein to outside across the inner and outer rims of the disc. The disc cartridge is provided with a recording and/or reproducing opening larger in size than the main cartridge body unit.
As a disc cartridge housing a disc as an information recording medium, there is known such one as disclosed in the U.S. Pat. No. 5,570,252. The disc cartridge disclosed in this Publication has an opening in a lateral surface of the main cartridge body unit. The magnetic head is introduced via this opening into the inside of the disc cartridge into sliding contact with the signal recording region of the magnetic disc. In this disc cartridge, the shutter member adapted for opening/closing the opening is mounted for performing movement along a lateral side of the main cartridge body unit.
Meanwhile, with the disc cartridge disclosed in the U.S. Pat. No. 4,510,546, in which the shutter member is moved in parallel along the front surface of the main cartridge body unit to open/close the recording and/or reproducing opening, it is difficult to provide a cartridge supporting portion sized sufficient to support the disc cartridge in stability on both sides of the front surface of the moving main cartridge body unit, such that it is difficult to load the disc cartridge on the recording and/or reproducing apparatus in stability.
Also, the disc cartridge as disclosed in the U.S. Pat. No. 4,614,990 is provided with a recording and/or reproducing opening larger in size than the main cartridge body unit, the shutter member for opening/closing the recording and/or reproducing opening is also increased in size, and moreover is mounted on the front side of the main cartridge body unit so that the shutter member will be moved from the center portion of the main cartridge body unit to the vicinity of the lateral sides of the main cartridge body unit. Therefore, a cartridge supporting portion engaged or supported by the positioning pins provided on the recording and/or reproducing apparatus cannot be provided on a corner of the front surface along which is moved the shutter member of the main cartridge body unit to render it difficult to load the disc cartridge on the recording and/or reproducing apparatus in stability.
Moreover, the disc cartridge disclosed in the U.S. Pat. No. 5,570,252, the magnetic head is inserted into the inside of the main cartridge body unit via a narrow opening formed in the lateral surface of the main cartridge body unit, there are imposed limitations on the recording and/or reproducing mechanism that can be used. This disc cartridge is extremely difficult to apply for accommodating an optical disc used in conjunction with an optical pickup device. Also, the shutter member is adapted for opening/closing an opening narrow in width and longer than it is wide, and hence it is narrow and elongated in profile to render it difficult to realize a stable movement.
It is therefore an object of the present invention to provide a disc cartridge in which a cartridge supporting portion is provided in a region of a larger area to render it possible to load the disc cartridge in stability in the recording and/or reproducing apparatus.
It is another object of the present invention to provide a disc cartridge in which an opening for exposing the disc-shaped recording medium to outside can be positively opened/closed despite the larger size of the opening and the disc cartridge can be loaded in stability on the recording and/or reproducing apparatus.
It is still another object of the present invention to provide a disc cartridge which can be inserted easily into the recording and/or reproducing apparatus.
It is yet another object of the present invention to provide a disc cartridge in which a shutter member for opening/closing the opening provided in the main cartridge body unit can be moved in stability to assure positive protection of the shutter member.
In view of the above objects, the present invention provides a disc cartridge for housing a disc-shaped recording medium adapted for recording information signals thereon, including a disc-shaped recording medium, a main cartridge body unit including a circular medium housing section for rotationally housing the disc-shaped recording medium, a recording and/or reproducing opening for exposing at least a portion of the disc-shaped recording medium to outside, and a driving opening for allowing intrusion of rotating driving means for rotationally driving the disc-shaped recording medium, a shutter mechanism is rotated along the major surface of the main cartridge body unit within a region provided with the medium housing section of the main cartridge body unit to open/close at least the recording and/or reproducing opening, and a plurality of cartridge supporting portions provided at a plurality of corners outside the region provided with the medium housing section of the main cartridge body unit. The cartridge supporting portions is supported by positioning means provided on the recording and/or reproducing apparatus.
At the plural corners of the main cartridge body unit outside the region of the main cartridge body unit provided with the medium housing section, there may be provided plural regions of a larger area. If cartridge supporting portions are provided in these regions, the disc cartridge may be loaded in stability on the recording and/or reproducing apparatus.
The front surface of the main cartridge body unit of the disc cartridge according to the present invention, by which the main cartridge body unit is inserted into the recording and/or reproducing apparatus, is formed to a continuously arcuate shape having a radius larger than that of the arc of the medium housing section, whereby a region of a larger area in which to provide cartridge supporting portions is provided on both sides of the front surface. Moreover, the disc cartridge can be inserted easily into the recording and/or reproducing apparatus by having the arcuate front surface as an inserting end surface.
Also, if a lock mechanism for regulating the opening of the shutter mechanism is provided in the region surrounded by the medium housing section in the main cartridge body unit and the front surface of the main cartridge body unit, the shutter mechanism can be positively held in its closure position. Since the region surrounded by the medium housing section and the front surface of the main cartridge body unit is able to constitute a spacing of a larger area, the lock mechanism can be readily constructed which is able to hold the shutter mechanism reliably.
In the disc cartridge according to the present invention, the region in which the shutter member is rotated is a spacing defined by facing inner and outer wall sections to allow for entrance of the shutter member. When rotated to the position of opening the recording and/or reproducing opening provided in the main cartridge body unit, at least a portion of the shutter member is housed within a spacing defined between the inner and outer wall sections.
The present invention also provides a disc cartridge for housing a disc-shaped recording medium adapted for recording information signals thereon, including a disc-shaped recording medium, a main cartridge body unit including a circular medium housing section for rotationally housing the disc-shaped recording medium, a recording and/or reproducing opening for exposing at least a portion of the disc-shaped recording medium to outside, and a driving opening for allowing intrusion of rotating driving means for rotationally driving the disc-shaped recording medium, a shutter mechanism including a first shutter member rotated along the major surface of the main cartridge body unit within a region provided with the medium housing section to open/close at least the recording and/or reproducing opening and a second shutter member for opening/closing the driving opening, a shutter housing section constituted by an inner wall member and an outer wall member facing each other, and a plurality of cartridge supporting portions provided outside the region of the shutter housing section so as to be supported by positioning means provided on the recording and/or reproducing apparatus. The shutter housing section is provided outside of a region of movement of the shutter mechanism and houses at least a portion of the shutter mechanism.
Other objects and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments and the claims.